The invention relates to Hall effect semiconductor devices wherein current carriers in the substrate are deflected by the Lorentz force of a perpendicularly applied magnetic field.
In one type of known device, carriers from an emitter region travel through a base region toward one or the other of a pair of spaced collector regions. The carriers are deflected toward one or the other of the collector regions according to the polarity of a perpendicularly applied magnetic field. An electric drift field is applied through the base region to enhance carrier movement from the emitter region towards the collector regions. Examples of this type of device are shown in "The Magnetic Field Sensitive Transistor--A New Sensor for Crankshaft Angle Position", Halbo and Heraldsen, Sensors for Automotive Systems, Society of Automotive Engineers, SP-458, Congress and Exposition Cobo Hall, Detroit, Feb. 25-29, 1980; and Fujikawa et al U.S. Pat. No. 3,668,439.
The present invention provides improvements to the above noted device, including columnating means and trimmer means. The columnating means is between the emitter region and the collector regions and columnates the emitted carriers to a centralized beam to be deflected by the magnetic field. The trimmer means provides accurate fine tuning control of the amount of deflection of the carrier beam, to insure that the beam is directed toward the one or the other collector region.
In preferred form, the columnating means comprises a pair of spaced auxiliary collector regions intermediate the emitter region and the primary collector regions. Carriers emitted from the emitter region outside of a given central angle or cone are collected by the auxiliary collectors and do not reach the primary collectors. Carriers emitted from the emitter region within the given central angle cone pass between the auxiliary collector regions and reach the primary collectors, thus affording a centralized columnated beam of carriers to be deflected by the magnetic field. The trimmer means applies a selectable electric field perpendicular to the carrier beam and along the same direction as deflection of carriers, to thus electrically control the amount of deflection and insure that the carrier beam reaches the one or other primary collector region.